In pathological diagnosis, quantifying an expression level of a biological material that is overexpressing in a tissue section can be very important information in predicting prognosis or determining a subsequent treatment plan. In such quantification of a biological material, an expression level of a specific biological material in a region of interest, which is a region to be analyzed that has been set in a tissue section, is analyzed; therefore, development of approaches has been desired that are capable of accurately performing the quantification of the biological material and extraction of the region of interest.
Accordingly, Patent Literature 1, for example, describes a method in which pixels with maximal luminance values are extracted as fluorescent bright spots using Top-hat transform or the like from a fluorescence image obtained by capturing an image of a tissue specimen in which a specific protein has been stained using fluorescent material accumulating particles and an expression level of the specific protein in the image is analyzed. According to the method described in Patent Literature 1, the fluorescent material accumulating particles have a high luminance per particle and in the fluorescence image, the biological material that has been stained fluorescently is observed in the form of dots; thus, the quantification is easy.
In addition, Patent Literature 2, for example, describes a method of calculating the number of particles included in each bright spot based on an average luminance value per fluorescent material accumulating particle. In the method described in Patent Literature 2, a similar fluorescence image as Patent Literature 1 is used to calculate luminance values of fluorescence emission bright spots, and the mode of the luminance values is used as an average luminance value per fluorescent material accumulating particle.